1. Field of the Invention
The present invention relates to a method for manufacturing a heat-dissipating structure of a rectifier, and particularly to a manufacturing method combining heat pipes in the heat-dissipating structure of a rectifier to enhance the heat-dissipating efficiency.
2. Description of the Prior Art
A generator, especially in an automobile, usually needs a rectifier to switch alternating current (AC) to direct current (DC), and then provides electric power for the automobile or charges a storage battery. Therefore, the stability of the rectifier greatly concerns the continuity of providing electric power. However, the temperature in the automobile engine is very high, and the rectifying diodes of the rectifier get hot after operating for a period of time. The two above-mentioned conditions may cause an irregular power supply. Therefore, the automotive generator needs a heat-dissipating structure for dissipating heat from the diodes.
Reference is made to FIG. 1, which is a heat-dissipating structure of a conventional rectifier. The heat-dissipating structure of the prior art has a cooling board 10a, a plurality of rectifying diodes embedded in the cooling board 10a, an insulated board 30a connected with the cooling board 10a, and a plurality of screwing bolts 40a. The cooling board 10a includes a plurality of fins 14a extending therefrom.
However, the conventional heat-dissipating structure of the rectifier only conducts heat via metal, so the efficiency of dissipating heat is still suboptimal. The thermal resistance is decided by the material conductivity and the effective area of volume. When the volume of the solid aluminum or copper heatsink reaches 0.006 stere (cubic meters), the thermal resistance cannot be reduced, even when the volume or area is enlarged. Besides, the conventional design must arrange the fins near the heat source, the rectifying diodes 20a, increasing not only manufacturing difficultly but also the total volume thereof. The generator therefore becomes bulky.
Although electronic devices use applied heat pipes to increase the heat-dissipating efficiency, heat pipes are still not used with the heat-dissipating structure of the rectifier. The reasons are that the shape of the rectifier is curved and complex because of the plural diodes spread on the rectifier, and the heat pipes are easily broken after bending. Therefore the heat pipes are not easily combined with the rectifier.